The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
A typical multiple speed transmission uses a combination of torque transmitting devices and gear sets to achieve a plurality of driving modes that include a plurality of out-of-Park driving modes and a Park mode. The out-of-Park driving modes generally include forward gear or speed ratios (i.e. a Drive mode), at least one reverse gear or speed ratio (i.e. a Reverse mode), and a Neutral mode. Selection of the various driving modes is typically accomplished by engaging a shift lever or other driver interface device that is connected by a shifting cable or other mechanical connection to the transmission. Alternatively, the selection of a driving mode may be controlled by an electronic transmission range selection (ETRS) system, also known as a “shift by wire” system. In an ETRS system, selection of the driving modes is accomplished through electronic signals communicated between the driver interface device and the transmission. The ETRS system reduces mechanical components, increases instrument panel space, enhances styling options, and eliminates the possibility of shifting cable misalignment with transmission range selection levers.
The ETRS system includes various components that enable the out-of-Park mode and Park mode, including a Park inhibit solenoid assembly (PISA). The PISA is operable to prevent the transmission from undesirably shifting from the out-of-Park mode to the Park mode. While typical PISA's are useful for their intended purpose, the employment of ETRS systems within applications having heavier fluid pressures and forces, such as trucks and sport utility vehicles, as well as applications in cold weather, requires an increased ability to prevent undesirable engagement of the Park mode. Accordingly, there is a need in the art for a PISA that provides locking features to prevent undesirable engagement of the Park mode while minimizing the size and weight of the PISA.